Scalp Edited Slides by Rama Abbady Dr. Heba Kalbouneh Associate - - PDF document

Scalp

Edited Slides by Rama Abbady

• Dr. Heba Kalbouneh

Associate Professor of Anatomy andHistology

• It is the soft tissue that covers the skull cap
• Extension:

Front: supercilliary arch Back: superior nuchal line Sides: zygomatic arch Highest point of the scalp is called Vertex

Scalp

Dr . Heba Kalbouneh Scalp is the hairy area of the head; سأرلا ةورف Frontal bone Occipital bone Zygomatic + temporal bone

To assist one in memorizing the names of the five layers of the scalp, use each letter of the word SCALP to denote the layer of thescalp

S- Skin C- Connective tissue (subcutanous tissue) A- Aponeurosis L- Loose connective tissue P- Pericranium (periosteum) Skull

Dr . Heba Kalbouneh Cutaneous Membrane Tendon of the inserted muscle Space filled with Periosteum of the cranial bones

• Inside the skull is the cranial cavity which contains the brain
• The brain is surrounded by 3 layers of connective tissue

called meninges, the outermost layer is called dura mater.

The SCALP consists of five layers: S- Skin C-Connective tissue (dense) A-Aponeurotic layer L-Loose connective tissue P-Pericranium The first three of which are intimately bound together and move as a unit

Dr . Heba Kalbouneh They move on the periosteum of the cranial bones

S- Skin C- Connective tissue A-Aponeurosis L- Loose connective tissue P- Periosteum

Dr . Heba Kalbouneh Fleshy part of a muscle, white rich is collagen type 1 Space filled with loose connective tissue

1- Skin Rich in hair follicles, sebaceous glands and eccrine sweat glands

Scalp is a common site for sebaceous cysts

Dr . Heba Kalbouneh

Sebaceous gland Sweat gland

The sebaceous gland secrete the oily material into the hair canal to lubricate the hair and the skin

Blockage of the ducts of the sebaceous gland or the hair canal with the oily material results in sebaceous cysts

• Accumulation of the oily material

2- Connective tissue Made of fibrous septa which unite the skin to the underlying aponeurosis It is often difficult to stop the bleeding of a scalp wound The blood vessels do not retract and close when lacerated because the connective tissue in which they are found holds them open Local pressure applied to the scalp is the

• nly satisfactory method of stopping the

bleeding Thus wounds of the scalp bleed profusely but heal very rapidly Contains numerous blood vessels, nerves, and fat

Dr . Heba Kalbouneh

• Also because of the fibrous septa

A B

A: Aponeurosis B: Space filled with loose connective tissue Diploic vein: drains the diploe of the bone

Fibrous septa

1- Unite the skin to the underlying aponeurosis of the occipitofrontalis muscle 2- Divide the connective tissue layer into small compartments 3- Hold the cut blood vessels open (in case of scalp wound)

Dr . Heba Kalbouneh

• When a blood vessel is lacerated, the normal

physiological response is : contraction, retraction and blood clot formation, BUT the fibrous septa here holds the cut blood vessel open  that’s why the wound of the scalp bleed profusely

• In order to stop bleeding, local pressure must be

applied

• Infection in this layer of the scalp is localized due to

the fibrous septa

Emissary veins

Emissary veins: are devoid of valves , connects the veins of the scalp (2nd layer) with the intracranial venous sinuses 1- Equalize the pressure between intracranial and extracranial veins 2- Selective cooling of the head

Emissary veins connect the veins

• utside the cranium to the venous

sinuses inside the cranium

!!!!!!! Serve as routes where infections are carried into the cranial cavity from the extracranial veins to the intracranial veins.

Dr . Heba Kalbouneh

Emissary vein: connects an extracranial vein with an intracranial vein within the cranial cavity but outside the brain Intracranial venous sinus This vein penetrates the connective tissue, aponeurosis, loose connective tissue, cranial bones and the intercanial cavity

Dr . Heba Kalbouneh Under the subcutaneous tissue there is dense type of fat that is not affected by obesity

Dr . Heba Kalbouneh

Consists of the occipitofrontalis muscle Occipitofrontalis has a frontal belly anteriorly and an occipital belly posteriorly and an aponeurotic tendon connecting the two The lateral margins of the aponeurosis are attached to the temporal fascia

3- Epicranial aponeurosis (Galea aponeurotica)

Muscles of the Scalp Occipitofrontalis Origin: Frontal belly: skin of the eyebrows Occipital belly: highest nuchal line/ superior nuchal line Insertion: Epicranial aponeurosis Nerve supply: Facial nerve (temporal and posterior auricular branches) Action: Moves scalp on skull The frontal bellies of the occipitofrontalis raises the eyebrows in expressions of surprise or horror (wrinkling of forehead).

Dr . Heba Kalbouneh

Contraction of muscles attached to the skin moves the skin producing facial expressions All the muscles of facial expression are supplied by the facial nerve

Frontalis muscle & Galea aponeurotica

Dr . Heba Kalbouneh

Contraction of this muscle produces transverse wrinkles

The tension of the epicranial aponeurosis, produced by the tone of the

• ccipitofrontalis muscles, is important in

all deep wounds of the scalp.

Dr . Heba Kalbouneh

The aponeurosis connects the frontalis and occipitalis muscles. If it is cut coronally. contraction of the muscle usually gapes the wound For satisfactory healing to take place, the opening in the aponeurosis must be closed with sutures

Laterally, the aponeurosis of this muscle is attached to the superior temporal line

Styloid process of the temporal bone

Mastoid process

Dr . Heba Kalbouneh

Course of facial nerve:

• It leaves the cranial cavity by passing through two

processes: styloid process & mastoid process

• The facial nerve emerges from the cranial cavity

from the stylomastoid foramen

The stylomastoid foramen In the interval between the styloid and mastoid processes

Dr . Heba Kalbouneh

Facial Nerve

As the facial nerve runs forward within the substance

• f the parotid salivary gland it

divides into its five terminal branches: 1-The temporal 2-The zygomatic 3-The buccal

4 The mandibular 5 The cervical

Posterior auricular nerve Facial nerve Parotid gland Temporal nerve

Dr . Heba Kalbouneh

(Cheek) Motor branches

• Before entering the parotid gland, the facial nerve

gives a branch that runs posterior to the auricle called posterior auricular nerve which supplies the occipital belly

• The frontal belly is supplied by the temporal branch

4- Loose areolar tissue The subaponeurotic space is the potential space beneath the epicranial aponeurosis and is filled with loose areolar tissue Remember the attachment of Epicranial aponeurosis layer!!! Frontalis muscle has no bony attachment

Blood accumulates in this layer spreads

• ver the entire extent of the aponeurosis

reaching the eyelid and presents as a black eye

Blow on the skull

Hemorrhage in the 4th layer of the scalp may cause raccoon eye

Dr . Heba Kalbouneh

(Spaced filled with loose connective tissue)

• Since the 4th layer of the scalp is a space, infection in this layer is diffused not localized
• Bleeding in the 4th layer of the scalp will diffuse in the space, but this diffusion is limited posteriorly and laterally

but not anteriorly

• Posteriorly: the occipital belly is attached to the superior nuchal lines
• Laterally: the aponeurosis is attached to the superior temporal line
• Anteriorly: no bony attachment, so the blood passes and fills the upper and lower eyelids

The subaponeurotic space contains emissary veins This layer is called the dangerous area of the scalp Infections in the subaponeurotic space can spread to intracranial venous sinuses through emissary veins (valveless) Infection spreads by the emissary veins (valveless) to the skull bones, causing

• steomyelitis of the flat bone through the dipolic vein.

Emissary vein Dipolic vein Intracranial venous sinus

Dr . Heba Kalbouneh

Dipolic vein: drains the diploe of the flat bone

5-Pericranium

• Is the periosteum covering the outer

surface of the skull bones.

• Removable, except in the area of sutures
• The periosteum on the outer surface of the

bones becomes continuous with the periosteum on the inner surface of the skull bones at the sutures . THEREFORE if there is any fluid collection beneath the pericranium (Cephalhaematoma/ subperiosteal hematoma) it will take the shape of the related bone

Dr . Heba Kalbouneh

Fibrous membrane

• Bleeding under the periosteum takes the shape of the underlying bone

(Subperiosteal hematoma/ Cephalhaematoma)

• Happens to the newborn because of the use of certain tools during delivery,

which may cause bleeding of one of the periosteal vessels

4 sensory 1 motor

Nerve supply of the scalp

10 sets of nerves on each side of the scalp 5 in front the auricle 5 behind the auricle 4 sensory 1 motor

Nerves in front the auricle 1 Supratrochlear nerve 2 Supraorbital nerve 3 Zygomaticotemporal nerve 4 Auriculotemporal nerve 5 Temporal branch of facial nerve supplying the frontal belly of

• ccipitofrontalis

Nerves behind the auricle 1- Great auricular nerve (ant rami C2 C3) 2- Lesser occipital nerve (ant rami C2 ) 3- Greater occipital nerve (post rami C2 ) 4- Third occipital nerve (post rami C3 ) 5- Posterior auricular branch of facial nerve supplying the occipital belly of occipitofrontalis

Dr . Heba Kalbouneh

• Sensory nerves behind the auricle only the lesser
• ccipital and the greater occipital nerves are required

Ventral rami

• f cervical

nerves Dorsal rami

• f cervical

nerves

• Skin of the face is supplied by branches of the trigeminal nerve
• The neck and the posterior surface of the scalp are supplied by spinal nerves (cervical nerves)
• Posterior surface of the scalp + posterior aspect of the neck  supplied by dorsal rami (C2-C4)
• Anterolateral aspect of the neck  supplied by ventral rami (C2-C4)
• Ventral rami form plexuses except in the thoracic area
• The cervical plexus is formed by ventral rami of C1,C2,C3,C4

Trigeminal nerve

Posterior rami (C2-C4) External

• ccipital

protuberance Acromion Ophthalmic nerve Mandibular nerve Maxillary nerve Anterior rami (C2-C4) Clavicle

• Anterior + Posterior rami of (C2-C4) only, because C1 has no cutaneous nerves

Maxillary nerve Mandibular nerve Ophthalmic nerve Sensory Nerves of the Face

Dr . Heba Kalbouneh

• The trigeminal nerve originates from the brain stem, it has a ganglion.
• The trigeminal ganglion is equivalent to the sensory ganglion in the dorsal root of the spinal nerves
• 3 branches originate from the trigeminal ganglion: ophthalmic, maxillary and mandibular.
• The ophthalmic branch leaves the cranial cavity through the superior orbital fissure.
• The maxillary nerve leaves through foramen rotundum, it then reaches the pterygopalatine fossa to pass

through the inferior orbital fissure to reach the floor of the orbit. It then changes its name to infraorbital nerve which emerges on the face by entering through the infra-orbital foramen.

• The mandibular nerve leaves through foramen ovale and then passes through the infratemporal fossa.

Trigeminal Ganglion

Zygomaticotemporal nerve

Auriculotemporal nerve

Supraorbital nerve Supratrochlear nerve

• The supraorbital and supratrochlear nerves are branches of the ophthalmic nerve
• The Zygomaticotemporal nerve is a branch of the maxillary nerve (covers the temporal area near the

zygomatic bone)

• The auriculotemporal nerve is a branch of the mandibular nerve (covers the temporal area near the auricle)
• The supraorbital nerve leaves through the supraorbital foramen
• The nerve that passes above the trochlea is called the supratrochlear nerve. The trochlea is in the most

superior, anterior, medial aspect of the orbit.

Great auricular n Lesser occipital n Third occipital n Greater occipital n

• Greater occipital nerve: covers large area of the occipit, a branch of

the dorsal ramus of C2

• Lesser occipital nerve: a branch from the cervical plexus (ventral

ramus of C2)

Sphenoid bone

Foramen ovale (mandibular nerve) Foramen rotundum (maxillary nerve) Foramen spinosum Superior orbital fissure (branches of ophthalmic nerve)

• The sphenoid bone has lesser wings, body and

greater wings Brain stem in the posterior cranial fossa

Trigeminal nerve Mandibular nerve Ophthalmic nerve Maxillary nerve

Dr . Heba Kalbouneh

The ophthalmic nerve gives 3 branches before entering the superior orbital fissure : 1. Frontal nerve (roof of the orbit) 2. Lacrimal nerve (the lacrimal gland) 3. Nasociliary nerve (Nasal wall of the orbit)

Supraorbital nerve

Dr . Heba Kalbouneh

Frontal nerve

Supratrochlear nerve Frontal nerve

Dr . Heba Kalbouneh

Medial to the supraorbital nerve

Zygomatic nerve Maxillary nerve

The zygomatic nerve is a branch from maxillary nerve, it has two branches: 1 Zygomaticotemporal nerve 2 Zygomaticofacial nerve

The maxillary nerve and its zygomatic branch pass through inferior

• rbital fissure

The maxillary nerve leaves through foramen rotundum, it then reaches the pterygopalatine fossa to pass through the inferior orbital fissure to reach the floor of the orbit. It then changes its name to infraorbital nerve which emerges on the face by entering through the a canal called the infraorbital canal. Pterygopalatine fossa

• The maxillary nerve gives a branch within the

pterygopalatine fossa called the zygomatic nerve

• The zygomatic nerve gives 2 branches while the

maxillary nerve changes its name to infraorbital nerve after passing through the infraorbital foramen

1- The zygomaticotemporal nerve

• A branch of thezygomatic

nerve ( maxillary nerve)

• Emerges in the temporal fossa

through a small foramen on the posterior surface of the zygomatic bone. It supplies the skin over the temple (Zygomaticotemporal foramen) 2- The zygomaticofacial nerve

• A branch of the zygomatic

nerve ( maxillary nerve)

• Passes onto the face through

a small foramen on the anterior side of the zygomatic bone. It supplies the skin over the prominence of the cheek (Zygomaticofacial foramen)

Dr . Heba Kalbouneh

Supratrochlear nerve

• A branch of the
• phthalmic division of

the trigeminal nerve (most medial)

• Winds around the

superior orbital margin and ascends over the forehead close to the median plane

• It supplies the scalp

nearly as far backward as the vertex.

Dr . Heba Kalbouneh

Supraorbital nerve

• A branch of the
• phthalmic division of

the trigeminal nerve

• Passes through the

supraorbital foramen and ascends over the forehead

• It supplies the scalp

as far backward as the vertex.

Dr . Heba Kalbouneh

Zygomaticotemporal nerve

• A branch of the

maxillary division of the trigeminal nerve

• Supplies the skin over

the temporal region

Note: Zygomaticotemporal foramen (present on the posterior surface of zygomatic bone

Dr . Heba Kalbouneh

Auriculotemporal nerve

• A branch of the

mandibular division of the trigeminal nerve

• Emerges from the

upper border of parotid gland

• Ascends in front of the

auricle

• Supplies the skin over

the temporal region.

Dr . Heba Kalbouneh

Lesser occipital nerve

• A branch of the

cervical plexus (C2)

• Supplies the skin over

the lateral part of scalp behind the auricle

Dr . Heba Kalbouneh

Greater occipital nerve

• A branch of theposterior

ramus of the second cervical nerve (C2)

• Supplies the skin over

the back of scalp as far forward as the vertex

Dr . Heba Kalbouneh

Out of 5 2 arteries (indirectly from internal carotid artery) 3 arteries (directly from the external carotid artery)

Blood supply of the scalp

5 sets of arteries on each side of the scalp 3 in front of the auricle 2 behind the auricle

Dr . Heba Kalbouneh

SupraorbitalA SupratrochlearA Superficial temporalA Posterior auricularA OccipitalA

Dr . Heba Kalbouneh

Common carotid artery

• Right common carotid: from the brachiocephalic artery
• Left common carotid artery: from arch of the aorta
• Begins: sternoclavicular joint
• Ends: upper border of the thyroid cartilage (C4).
• Divisions: External and internal carotid arteries

Dr . Heba Kalbouneh

Common carotid artery

Thyroid cartilage

Dr . Heba Kalbouneh

• It ascends upward inside the neck without giving any branch
• Just at the level of the superior border of the thyroid cartilage,

it gives 2 branches :

• 1. Internal carotid artery (pierces the base of the skull to enter

the cranial cavity)

• 2. External carotid artery (supplies superficial structures)

Internal carotid artery Enters the carotid canal in the skull Ophthalmic artery is one of its branches Ophthalmic artery enters the

• rbit through optic canal

It gives two branches: 1-Supraorbital artery 2- Supratrochlear artery Has no branches in the neck

Ophthalmic artery

Dr . Heba Kalbouneh

• It pierces the base of the skull to enter

the cranial cavity through carotid canal

• Supplies the brain

External carotid artery

Medial to the internal carotid artery, then passes backward and lateral to it.

Dr . Heba Kalbouneh

 Branches:

• a. Superior thyroid artery
• b. Ascending pharyngeal

artery

• c. Lingual artery
• d. Facial artery
• e. Occipital artery
• f. Posterior auricular

artery

• g. Superficial temporal

artery

• h. Maxillary artery

External carotid artery

Some American Ladies Find Our Petra So Magnificent

Superficial temporalA Maxillary A passesdeep to mandible

These are the two terminal branches

• f ECA

Dr . Heba Kalbouneh

• The occipital artery and the posterior auricular artery supply the side

posterior to the auricle

 The external carotid artery

terminates as two branches (within the parotid gland ):

• 1. Maxillary artery passes deep to

the neck of the mandible

• 2. Superficial temporal artery

emerges from the upper border

• f parotid gland

Superficial temporal artery

Dr . Heba Kalbouneh

• The external carotid artery ascends inside the

neck and gives many branches there, it then enters the parotid gland

• Superficial temporal artery becomes more

prominent as we age because it’s superficial in location and due to loss of fat so it becomes more

• bvious at the temporal side

Supratrochlear artery

Ophthalmic artery

• A branch of ophthalmic

artery

• Ascends over the

forehead in company with the supratrochlear nerve

• Supplies the upper

eyelid, and the skin of the forehead and the scalp.

Dr . Heba Kalbouneh

Supraorbital artery

Dr . Heba Kalbouneh

• A branch of ophthalmic

artery

• Passes through the

supraorbital foramen

• Ascends over the forehead

in company with the supraorbital nerves

• Supplies the upper eyelid,

and the skin of the forehead and the scalp.

• The smaller terminal

branch of the external carotid artery

• Ascends in front of the

auricle

• Crosses over the root of

zygomatic arch (pulse can be felt there)

• It divides into anterior and

posterior branches, which supply the skin over the frontal and temporal regions.

Superficial temporal artery

Dr . Heba Kalbouneh

Posterior auricular artery

• A branch of External

carotid artery

• Ascends behind the auricle

to supply the lateral part of scalp behind the auricle

Dr . Heba Kalbouneh

Occipital artery

• A branch of External

carotid artery

• Supplies the skin over the

back of the scalp and reaches as high as the vertex

Dr . Heba Kalbouneh

Anatomically, it is useful to remember in an emergency that all the superficial arteries supplying the scalp ascend from the face and the neck. Thus, in an emergency situation, encircle thehead just above the ears (auricle) and eyebrows (superciliary arches) with a tie, shoelaces, or even a piece of string and tie it tight. Then insert a pen, pencil, or stick into the loop and rotate it so that the tourniquet exerts pressure on the arteries

Dr . Heba Kalbouneh